Base features a lightweight, aluminum body with integral scope rings. This creates a solid mount that won't shift or loosen up, maintaining exact target alignment shot after shot. The traditional ring/base joint is eliminated, reducing the possibility of the scope shifting under the stress of recoil. Notes:Socket head cap screws included for mounting to firearmEach mount is specifically machined to fit the particular firearmRing heights vary depending on the specific firearm and base machining. Please use the average height to select the correct height for mounting.